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File indexing completed on 2021-02-14 13:07:51

0001 #ifndef _CSCRADIAL_STRIP_TOPOLOGY_H_
0002 #define _CSCRADIAL_STRIP_TOPOLOGY_H_
0003 
0004 #include "Geometry/CommonTopologies/interface/RadialStripTopology.h"
0005 
0006 /**
0007  * \class RadialStripTopology
0008  * A StripTopology in which the component strips subtend a constant
0009  * angular width, and, if projected, intersect at a point.
0010  *
0011  * \author Tim Cox
0012  *
0013  * WARNING! Wherever 'float strip' is used the units of 'strip' are angular
0014  * widths of each strip. The range is from 0.0 at the extreme edge of the
0015  * 'first' strip at one edge of the detector, to nstrip*angular width
0016  * at the other edge. <BR>
0017  * The centre of the first strip is at strip = 0.5 <BR>
0018  * The centre of the last strip is at strip = 0.5 + (nstrip-1) <BR>
0019  * This is for consistency with CommonDet usage of 'float strip' (but
0020  * where units are strip pitch rather than strip angular width.)<BR>
0021  *
0022  * WARNING! If the mid-point along local y of the plane of strips does not correspond
0023  * to the local coordinate origin, set the final ctor argument appropriately. <BR>
0024  *
0025  * Original  version, allows inheritance 
0026  */
0027 
0028 class CSCRadialStripTopology : public RadialStripTopology {
0029 public:
0030   /** 
0031    * Constructor from:
0032    *    \param ns number of strips
0033    *    \param aw angular width of a strip
0034    *    \param dh detector height (usually 2 x apothem of TrapezoidalPlaneBounds)
0035    *    \param r radial distance from symmetry centre of detector to the point at which 
0036    *    the outer edges of the two extreme strips (projected) intersect.
0037    *    \param yAx orientation of local y axis: 1 means pointing from the smaller side of
0038    *    the module to the larger side (along apothem), and -1 means in the 
0039    *    opposite direction, i.e. from the larger side along the apothem to the 
0040    *    smaller side. Default value is 1. 
0041    *    \param yMid local y offset if mid-point of detector (strip plane) does not coincide with local origin.
0042    *    This decouples the extent of strip plane from the boundary of the detector in which the RST is embedded.
0043    */
0044   CSCRadialStripTopology(int ns, float aw, float dh, float r, float yAx = 1.f, float yMid = 0.);
0045 
0046   /** 
0047    * Destructor
0048    */
0049   ~CSCRadialStripTopology() override {}
0050 
0051   // =========================================================
0052   // StripTopology interface - implement pure virtual methods
0053   // =========================================================
0054 
0055   /** 
0056    * LocalPoint on x axis for given 'strip'
0057    * 'strip' is a float in units of the strip (angular) width
0058    */
0059   LocalPoint localPosition(float strip) const override;
0060 
0061   /** 
0062    * LocalPoint for a given MeasurementPoint <BR>
0063    * What's a MeasurementPoint?  <BR>
0064    * In analogy with that used with TrapezoidalStripTopology objects,
0065    * a MeasurementPoint is a 2-dim object.<BR>
0066    * The first dimension measures the
0067    * angular position wrt central line of symmetry of detector,
0068    * in units of strip (angular) widths (range 0 to total angle subtended
0069    * by a detector).<BR>
0070    * The second dimension measures
0071    * the fractional position along the strip (range -0.5 to +0.5).<BR>
0072    * BEWARE! The components are not Cartesian.<BR>
0073    */
0074   LocalPoint localPosition(const MeasurementPoint&) const override;
0075 
0076   /** 
0077    * LocalError for a pure strip measurement, where 'strip'
0078    * is the (float) position (a 'phi' angle wrt y axis) and
0079    * stripErr2 is the sigma-squared. Both quantities are expressed in
0080    * units of theAngularWidth of a strip.
0081    */
0082   LocalError localError(float strip, float stripErr2) const override;
0083 
0084   /** 
0085    * LocalError for a given MeasurementPoint with known MeasurementError.
0086    * This may be used in Kalman filtering and hence must allow possible
0087    * correlations between the components.
0088    */
0089   LocalError localError(const MeasurementPoint&, const MeasurementError&) const override;
0090 
0091   /** 
0092    * Strip in which a given LocalPoint lies. This is a float which
0093    * represents the fractional strip position within the detector.<BR>
0094    * Returns zero if the LocalPoint falls at the extreme low edge of the
0095    * detector or BELOW, and float(nstrips) if it falls at the extreme high
0096    * edge or ABOVE.
0097    */
0098   float strip(const LocalPoint&) const override;
0099 
0100   /** 
0101    * Pitch (strip width) at a given LocalPoint. <BR>
0102    * BEWARE: are you sure you really want to call this for a RadialStripTopology?
0103    */
0104   float localPitch(const LocalPoint&) const override;
0105 
0106   /** 
0107    * Angle between strip and symmetry axis (=local y axis)
0108    * for given strip. <BR>
0109    * This is like a phi angle but measured clockwise from y axis 
0110    * rather than counter clockwise from x axis.
0111    * Note that 'strip' is a float with a continuous range from 0 to 
0112    * float(nstrips) to cover the whole detector, and the centres of
0113    * strips correspond to half-integer values 0.5, 1.5, ..., nstrips-0.5
0114    * whereas values 1, 2, ... nstrips correspond to the upper phi edges of
0115    * the strips.
0116    */
0117   float stripAngle(float strip) const override;
0118 
0119   /** 
0120    * Total number of strips 
0121    */
0122   int nstrips() const override { return theNumberOfStrips; }
0123 
0124   /** 
0125    * Height of detector (= length of long symmetry axis of the plane of strips).
0126    */
0127   float stripLength() const override { return theDetHeight; }
0128 
0129   /** 
0130    * Length of a strip passing through a given LocalPpoint
0131    */
0132   float localStripLength(const LocalPoint&) const override;
0133 
0134   // =========================================================
0135   // Topology interface (not already implemented for
0136   // StripTopology interface)
0137   // =========================================================
0138 
0139   MeasurementPoint measurementPosition(const LocalPoint&) const override;
0140 
0141   MeasurementError measurementError(const LocalPoint&, const LocalError&) const override;
0142 
0143   /** 
0144    * Channel number corresponding to a given LocalPoint.<BR>
0145    * This is effectively an integer version of strip(), with range 0 to
0146    * nstrips-1.  <BR>
0147    * LocalPoints outside the detector strip plane will be considered
0148    * as contributing to the edge channels 0 or nstrips-1.
0149    */
0150   int channel(const LocalPoint&) const override;
0151 
0152   // =========================================================
0153   // RadialStripTopology interface itself
0154   // =========================================================
0155 
0156   /** 
0157    * Angular width of a each strip
0158    */
0159   float angularWidth() const override { return theAngularWidth; }
0160 
0161   /** 
0162    * Phi pitch of each strip (= angular width!)
0163    */
0164   float phiPitch(void) const override { return angularWidth(); }
0165 
0166   /** 
0167    * Length of long symmetry axis of plane of strips
0168    */
0169   float detHeight() const override { return theDetHeight; }
0170 
0171   /** 
0172    * y extent of strip plane
0173    */
0174   float yExtentOfStripPlane() const override { return theDetHeight; }  // same as detHeight()
0175 
0176   /** 
0177    * Distance from the intersection of the projections of
0178    * the extreme edges of the two extreme strips to the symmetry
0179    * centre of the plane of strips. 
0180    */
0181   float centreToIntersection() const override { return theCentreToIntersection; }
0182 
0183   /** 
0184    * (y) distance from intersection of the projections of the strips
0185    * to the local coordinate origin. Same as centreToIntersection()
0186    * if symmetry centre of strip plane coincides with local origin.
0187    */
0188   float originToIntersection() const override { return (theCentreToIntersection - yCentre); }
0189 
0190   /**
0191    * Convenience function to access azimuthal angle of extreme edge of first strip 
0192    * measured relative to long symmetry axis of the plane of strips. <BR>
0193    *
0194    * WARNING! This angle is measured clockwise from the local y axis 
0195    * which means it is in the conventional azimuthal phi plane, 
0196    * but azimuth is of course measured from local x axis not y. 
0197    * The range of this angle is
0198    *  -(full angle)/2 to +(full angle)/2. <BR>
0199    * where (full angle) = nstrips() * angularWidth(). <BR>
0200    *
0201    */
0202   float phiOfOneEdge() const override { return thePhiOfOneEdge; }
0203 
0204   /**
0205    * Local x where centre of strip intersects input local y <BR>
0206    * 'strip' should be in range 1 to nstrips() <BR>
0207    */
0208   float xOfStrip(int strip, float y) const override;
0209 
0210   /**
0211    * Nearest strip to given LocalPoint
0212    */
0213   int nearestStrip(const LocalPoint&) const override;
0214 
0215   /** 
0216    * y axis orientation, 1 means detector width increases with local y
0217    */
0218   float yAxisOrientation() const override { return theYAxisOrientation; }
0219 
0220   /**
0221    * Offset in local y between midpoint of detector (strip plane) extent and local origin
0222    */
0223   float yCentreOfStripPlane() const override { return yCentre; }
0224 
0225   /**
0226    * Distance in local y from a hit to the point of intersection of projected strips
0227    */
0228   float yDistanceToIntersection(float y) const override;
0229 
0230   friend std::ostream& operator<<(std::ostream&, const RadialStripTopology&);
0231 
0232 private:
0233   int theNumberOfStrips;          // total no. of strips in plane of strips
0234   float theAngularWidth;          // angle subtended by each strip = phi pitch
0235   float theDetHeight;             // length of long symmetry axis = twice the apothem of the enclosing trapezoid
0236   float theCentreToIntersection;  // distance centre of detector face to intersection of edge strips (projected)
0237   float thePhiOfOneEdge;          // local 'phi' of one edge of plane of strips (I choose it negative!)
0238   float theYAxisOrientation;      // 1 means y axis going from smaller to larger side, -1 means opposite direction
0239   float yCentre;  // Non-zero if offset in local y between midpoint of detector (strip plane) extent and local origin.
0240 };
0241 
0242 #endif